package ex43;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Locale;

public class Main {
	
	public static void main(String[] args) throws IOException {
		
		InputStreamReader it = new InputStreamReader(System.in);
		BufferedReader in = new BufferedReader(it);
		
		String input, inputParts[];
		double a, b, c, area, perimeter;
		
		input = in.readLine();
		inputParts = input.split(" ", 3);
		
		a = Double.parseDouble(inputParts[0]);
		b = Double.parseDouble(inputParts[1]);
		c = Double.parseDouble(inputParts[2]);
		
		if ((a < b + c) && (b < a + c) && (c < a + b)) {
			perimeter = a + b + c;
			System.out.printf(Locale.ENGLISH, "Perimetro = %.1f\n", perimeter);
		} else {
			area = (c * (a + b)) / 2;
			System.out.printf(Locale.ENGLISH, "Area = %.1f\n", area);
		}
		
	}

}
